Division of Animal Welfare, DCR-VPHI, Vetsuisse Faculty, University of Bern, Länggassstrasse 120, 3012, Bern, Switzerland.
Animal Behaviour, Cognition and Welfare Group, School of Life Sciences, University of Lincoln, Lincoln, LN6 7DL, UK.
Sci Rep. 2018 Jun 27;8(1):9756. doi: 10.1038/s41598-018-28079-5.
Recently, there has been a move towards positive reinforcement using food rewards in animal training. By definition, rewards function as reinforcers if they increase or maintain the frequency of behaviour that they follow. However, in operant conditioning tasks animals frequently show systematic changes in performance - in particular a reduction in responding over time. One suggested strategy to avoid such performance decrements is to provide a variety of food rewards, rather than the same food reward in all trials. The enhancement of appetitive behaviour and consumption by reward variation is referred to as 'variety effect'. We investigated whether dogs preferred a variable or a constant food reward in a concurrent two-choice test. Of 16 dogs, six subjects showed a significant preference for the varied food reward and six for the constant food reward, while four dogs exhibited no significant preference for either option. At the group level, there was a significant effect of block: preference for the varied food reward increased across six blocks of ten trials each. Thus, although some individuals may prefer a single, favourite food reward in the short term, introducing variation in reward types may maintain dogs' motivation in operant tasks over a longer time period.
最近，在动物训练中，人们开始倾向于使用食物奖励来进行正向强化。从定义上讲，如果奖励能够增加或维持紧随其后的行为的频率，那么它们就具有强化作用。然而，在操作性条件反射任务中，动物的表现经常会出现系统的变化——特别是随着时间的推移，反应次数会减少。为避免这种表现下降，一种建议的策略是提供多种食物奖励，而不是在所有试验中都使用相同的食物奖励。通过奖励变化来增强食欲和消费的现象被称为“多样性效应”。我们调查了狗在同时进行的两项选择测试中，是更喜欢可变的还是固定的食物奖励。在 16 只狗中，有 6 只对可变的食物奖励表现出明显的偏好，6 只对固定的食物奖励表现出明显的偏好，而 4 只狗对这两种选择都没有明显的偏好。从群体水平来看，各区块存在显著影响：随着每十次试验为一组的六个区块的进行，对可变食物奖励的偏好增加。因此，尽管一些个体可能在短期内更喜欢单一的、喜欢的食物奖励，但引入奖励类型的变化可能会在较长时间内维持狗在操作性任务中的动力。
